1. Field of the Invention
The present invention relates to a wideband wireless mobile communication system using a plurality of antennas, and more particularly, to a method of processing control information on a physical channel.
2. Discussion of the Related Art
In next generation mobile communication and wireless transmission systems, an improved transmission rate and system capacity in a multi-cell environment have been demanded. To meet such a demand, studies on a multiple-input multiple-output (MIMO) system, which transmits data using multiple antennas, have been conducted. To improve the transmission rate of data in a multi-cell environment, a closed-loop MIMO system improves transmission capabilities using channel information.
In a MIMO system using a frequency division duplex (FDD) scheme, a user equipment (UE) can recognize information as to a reception channel using received data, whereas an eNode B (eNB) cannot know the channel information without feedback of specific channel information. Since the eNB can greatly improve system capabilities through adaptive channel transmission using the channel information of a downlink, the channel information needs to be fed back so that the eNB can recognize the channel information. When uplink/downlink in time division duplex (TDD) use the same frequency band, since frequency channel characteristics of uplink/downlink of the eNB and the UE are the same, the eNB cannot estimate the reception channel information of the UE in the case where a time-varying characteristic of a channel is not substantial.
In a closed-loop system using a MIMO scheme, general channel feedback information includes a channel quality indicator (CQI), a precoding matrix index (PMI), and rank information (RI).
Time and frequency resources, that can be used by a UE to report the CQI, PMI, and RI, may be controlled by an eNB. The above control information may be reported periodically or aperiodically. For spatial multiplexing, the UE may determine RI corresponding to the number of available transmission layers.
The UE may transmit CQI, PMI, and RI reporting on a physical uplink control channel (PUCCH) in subframes in which a physical uplink shared channel (PUSCH) is not allocated. The UE may transmit CQI, PMI, and RI reporting on the PUSCH in subframes with PUSCH allocation.
Meanwhile, data and control sequences transmitted from a media access control (MAC) layer to a physical layer are encoded and then provide transport and control services through a radio transmission link. A channel coding scheme is comprised of a combination of processes of error detection, error correction, rate matching, interleaving, and mapping of transport channel information or control information to a physical channel. The control information includes the CQI, PMI, and RI.
Control information, and data information from a transport channel may be multiplexed to generate a multiplexed sequence. The control information may be classified into one or more types according to properties thereof and various multiplexing schemes may be considered according to the number of classified types. If only one type of control information is present, when data information and control information are multiplexed, the control information may or may not overwrite the data information. If two types of control information are present, the control information is divided into a first type of control information and a second type of control information. If the second type of control information is more important than the first type of control information, data information and control information may be multiplexed in a manner that the first type of control information overwrites or does not overwrite the data information. Next, the second type of control information may or may not overwrite the multiplexed data information and/or the first type of control information.